Oil resistant conjugated diene-heterocyclic nitrogen base copolymers



2,848,442 OIL RESISTANT CONJUGATED DIENE-HETERO- CYCLIC NITROGEN BASE CGPOLYMERS Joseph F. Svetlik, Sr., Phillips, Tex, assignor to Phillips Petroleum Company, a corporation of Delaware No Drawing. Application April 11, 1955 Serial No. 500,685 7 Claims. (Cl. 260-821) The invention relates to oil resistant rubber. In a further aspect this invention relates to a method by which the oil resistance of rubbery copolymers of conjugated dienes with copolymerizable heterocyclic nitrogen bases of the pyridine and quinoline series can be very considerably improved. In a further aspect this invention relates to the products produced by this process.

In a copending application, Pritchard Serial No. 284,448, filed April 25, 1952, and now abandoned, it is disclosed that the properties of polymers of conjugated dienes and copolymerizable heterocyclic nitrogen bases can be modified by treatment with quaternizing agents such as .alkyl halides, alkyl sulfates, and many additional reactive compounds. That application discloses that rubbery polymers can be made more oil resistant by treatment with the quaternizing agents.

I have discovered that a particular quaternizing agent produces products which are characterized by a very substantial improvement in oil resistance when compared to products produced by the quaternizing agents disclosed in the Pritchard application and the other properties of these products, such as high tensile strength, low freeze point, and cold compression set are maintained or improved. This new quaternizing agent is chloranil, sometimes identified as tetra-chloroquinone. The chloranil performs the dual function of a quaternizing agent and a vulcanizing agent so that rubbery, oil resistant polymeric materials can be made containing no sulfur or other conventional vulcanizing agents. However, I frequently include a conventional vulcanizing agent with the chloranil where the presence of sulfur is not objectionable.

The following are objects of my invention:

An object of my invention is to provide oil resistant rubber. A further object of my invention is to improve the oil resistance of polymers of conjugated dienes with copolymerizable heterocyclic nitrogen bases of the pyridine and quinoline series. A further object of my invention is to provide oil resistant rubber prepared from V polymers of conjugated diene with the heterocyclic nitrogen bases, said rubber containing no sulfur in the cured composition Other objects and advantages of this invention will be apparent to one skilled in the art upon reading this disclosure.

The following examples illustrate specific embodiments of my invention.

rates Patent Example I Parts by weight Water 180 Butadiene 85 Z-methyl-S-vinylpyridine 15 Sodium fatty acid soap 4.3 K S O 0.3 Tert-dodecyl mercaptan Variable Shortstop: Goodrite 3955 0.15

Antioxidant (percent based on polymer): phenylbeta-naphthylamine 1 50/50 mixture of sodium dimethyldithiocarbamate and sulfur in the form of sodium polysulfide.

Results of the several runs were as follows:

Convertert-Do- Mooney sion, Perdecyl Mer- (ML-4) Time, Hours cent oaptan, Stripped part The butadiene/Z-methyl 5 vinylpyridine rubbery copolymer was compounded in accordance with the following recipe using chloranil, benzal chloride, or epichlorohydrin as the quaternizing agent.

2 Dibutyl carbitol formal. 3 Benzothiazyl disulfide.

Two additional runs were made using chloranil in the compounding recipe given above except that sulfur and Altax were omitted.

The samples were milled, cured 30 minutes at 307 F., and physical properties determined. The following results were obtained:

Quaternizing Agent 212 F. Cold Compression /30 Isooctane/ l Com- E1onga-- Set l Toluene Skydrol,

' pression Tensile, tion, Shore Percent Set, p. s. i. Percent Hardness Swelled Type Parts Percent Relaxed, Relaxed, Percent Percent 10 sec. 30 min. Swelled Extracted 3 6. 8 2, 550 190 73 74. 9 43. 3 96. 8 6. 9 53. 4 5 5. 8 2, 870 79 78. 7 44. 9 75. l 6. 6 45. 9 Ohloranil l0 5. 6 3, 110 86.5 86. 7 69. 9 52. 5 6. 5 38. 0 2 5 2. 2 2, 400 76 71. 7 40. 2 87. 7 7. 0 47. 9 2 l0 2. 8 2, 800 110 83. 5 85. 6 61. 9 60. 8 6. 7 40. 3 5 6. 8 2, 650 280 66 69. 8 34. 6 109. 2 8. 0 62. 1 d 10 6. 3 2, 800 245 71 83. 5 53. 9 93. 0 7. 6 59. 2 Bemal 01110 e 15 6.8 3, 250. 270 74. 5 92. a 71. a 75. a 8.0 59. 9 20 6. 6 3, 120 260 72. 5 93. 1 72. 7 73. 4 8. 5 61. 5 h in 5 15. 5 1, 610 290 50. 5 84. 6 63. 1 162. 9 9. 1 81. 8 EP1ch1T Ydf 10 18. a 1, 400 275 59 88. 2 73. 2 175. 7 9. 5 84.2 None 9.0 2, 220 310 61. 5 73. 9 38. 5 151.5 8. 5 78. 5

Immersed Samples Freeze Point 70/30 Isooctane/ Skydrol compounded Quaternizing Agent Parts Toluene MS Tensile, Elong., Tensile, Elong, T-R,C. Gehman,

p. s. i. Percent p. s. i. Percent 3 710 so 1, 210 115 -70 --72 45 5 1, 040 70 1,600 110 71 73 44 Chloranil 1, 220 60 1, 600 70 62 44 1 5 660 so 1, 240 100 72 72 4s. 5 4 10 960 50 1,180 60 -72 46 5 its a a 10 760 100 381ml ohlmde 590 so 1, 430 160 69 27 180 "0 5 Eplchmmhydnn 13 120 55 440 140 71 73 80 None 310 90 610 155 70 72 36 l 45 minutes cure time.

I Sulfur and Altax were omitted from these samples.

The oil resistance of the stocks was judged on the basis Parts by weight of tensile strength following immersion for 70 hours in Z-methyl-S-vmylpyndme -s 15 a solvent at 158 F. (ASTM 471-49T). Swelling and Sodium fatty and soap 4.3 extraction determination Were made following 48 hours 25 NaOH 0.045 immersion at 158 F. in 70/30 isooctane/toluene mix- K S O 0.3 ture and in Skydrol (a high boiling phosphate ester used Tert-doceyl mercaptan 0.29, 0.3 as a pressure transfer medium for aircraft systems). Shortstop: Goodntc 3955 0.15

Examination of this table shows that an oil resistant Ant o ldant (percent based on polyme stock containing chloranil is superior to stocks containing phenyl-beta-naphthylamme 2.0 the other quaternizing agents, benzal chloride or epichlorohydrin. For instance, the percent swell and extrac- Results of the runs were as follows tion data show that a small amount of chloranil, 3 parts, has a greater effect than 5 parts of either of the other T H C u t Mooney (ML-4) quaternizing agents as far as the percent extracted by g f i the isooctane/toluene mixture is concerned. This table Blowdozvn Shipped also shows that stocks possessing these good properties are obtained even when the vulcanizing agent and the 11% 12;: accelerator were omitted. "g

Example II 40 Products from the two runs were blended to glve a Two runs were made for the preparation of an 85/15 62 Mooney rubber. butadiene/2-methyl-5vinylpyridine copolymer by emul- This rubber was compounded in accordance with the sion polymerization at 122 F. in accordance with the recipe given in Example I using varying amounts of following formulation: chloranil and diphenyldichloromethane. The materials Parts by weight were milled, cured 30 minutes at 307 F., and the Water 180 physical properties were determined. The results are Butadiene 85 shown in the following table.

Quaternizing Agent 79/30 Isooctane/Tol- Gom- Comuene pression Tensile, Elongapounded Shore Sltydrol, Set, Perp. s. i. tion, MS 1% Hard- Swelled. cent Percent at 212 F. ncss swelled, Ex- Percent Type Parts Percent tracted, Percent 3 s. 4 2, 660 185 57. 5 71. 5 96. 4 7. 7 e Ohloranil 5 s. 0 2, 890 145 58. 5 76. a so. 7 o. 7 47. 2 10 7. 4 3,120 110 57. 5 s3. 5 .15. 5 o. 0 40. o Diphenyldichlo- 10 7.1 3,180 320 30 68.5 91.8 9.4 59.7 romethane 20 11.6 2, 930 250 26.5 71 69.4 9.8 09.4 None 11. 0 2, 460 320 32 5s. 5 14s. 4 a. s1. 1)

Immersed Sample 1 Cold Compression Quaternizlng Agent Set.

/30 Isooctaue/ Skydrol Toluene Type Parts Tensile, Elongation, Tensile, Elongation, Relaxed, Relaxed,

p. s. 1. Percent p. s. i. Percent 10 sec. 15 min.

a 530 80 1,070 70. 3 37. 4 Chloram'l 5 550 50 1, 430 so. 0 4o. 1 g 38 1, 648 7 9o. 1 7 1,17 s7. 8 7 Dlphenyldmhlommetmm 20 790 100 910 130 92.5 73.8 None 300 90 760 69. 8 37. 6

1 45 minutes cure time.

This table shows that the rubber cured with chloranil is more resistant to the solvent shown than is the rubber treated with the diphenyldichloromethane. Once again, a smaller amount of the preferred quaternizing agent has a greater effect than the larger amount of the other quaterm'zing agent when the extraction data are considered.

minutes at 307 F., and electrical resistivity determined.

The following results were obtained:

Example III N j 111 551 51 he butadiene/Z-methyI-S-vinylpyridine rubber -de- 10 PER 0111mm 53135 75,, scribed in Example II was compounded us1ng the followmg p 5 353,000 134 Parts by Weight Exam le V 1 n 15 v p Two runs were made for the copolymerization of buta- Butadiene/zmethy1 5 vmy1pyridme rubber 100 100 diene w1tl1 2 -v1nyl-5-ethylpyr1d1ne in aqueous emulsion 100 at 140 F., using the following recipe: x g l Zinc oxide 5 5 Parts y welglt Stearic ficld 1.5 1. 5 Water 2 1.5 1. Egg 1 L5 L5 Butadlene 85 TP-QOB 10 Benzal chloride or chloraml variable variable 2 vlpyl 5 ethylpyfldme Sod1um fatty acid soap 8 1 As in Example 1. NaOI-I 0.10 The stocks were milled and cured 30 minutes at 307 F. Daxad 11 0.30 and physical properties determined. The following results K S O 0.40 Were obtained: Tert-dodecyl mercaptan 0.35, 0.80

70/30 Isooctane/ Com- Com- Toluene 1 Benzal Ohlo- Carbon pres- Tensile, Elongapounded Shore Skydrol, Chloride, ranil, Black sion p. s. i. tion, MS 1% Hard- Swelled, Parts Parts Set, Percent at 212 F. ness Swelled, Ex- Percent Percent Percent tracted, Percent 15 Gastex 6. 0 2, 990 160 35. 5 77 70. 6 6. 0 51. 9 20 Gastex 6. 9 3, 170 220 33 78 61. 0 6. 3 52. 4 5 Gastex 6. 7 2, 930 126 67. 5 83 53.6 5. 6 40. 1

15 Thermax 8.8 1,830 325 31.5 71.5 83.0 5.0 52.0 20 Thermax 7.1 1,930 335 73.5 57.1 5.3 52.7 5 Thermax 6. 4 l, 950 155 57. 5 80 67. 8 4. 6 37. 6

Immersed Sample Cold Compression Set Benzal 70/30 Isooctane/ Skydrol Chloride, Chloranil Carbon Toluene Parts Parts Black Tensile, Elonga- Tensile, Elonga- Relaxed, Relaxed, p. s. 1. tion, p. s. i. tion, 10 sec. 30 min.

Percent Percent 15 Gastex 940 90 1, 460 140 90. 09 67. 3 20 Gastex 1, 110 100 1, 500 150 92. 9 77. 1 5 Gastex 910 1, 490 so 81. 6 40. 9

15 Thermax 770 180 970 270 90.3 67.0 20 Thermax 880 190 1,000 320 90.6 73.5 5 Thermax s70 80 1, 220 160 so. 6 46. 1

1 minutes cure time. 2 75 minutes cure time.

Example IV The polymerization recipe for the preparation of a 75/25 butadiene/2-methy1-5-vinylpyridine polymer pre- Polymerization d were as f ll pared at 4 1 F. was as follows:

Parts by weight Water 180 I Butadiene 75 t P t I'gixne, Converwing ercap an ar ours sion y y py P ht St Potassium fatty acid soap 6 KOH 11.4 85 103 KCl 0.2 14.0 90 2s K P O 0.165 1 080 11 1 0 0.139 Diisopropylbenzene hydroperoxide 0.107 Tert-dodecyl mercaptan 0.32 Polymers from the two runs were blended to give a Shortstop: Goodrite 3955 0.15 product having a Mooney value of 53. Antioxidant (percent based on polymer): phenyl The butadiene/Z-vinyl-S-ethylpyridine copolymer was beta-naphthylamine 2.0 compounded in accordance with the following recipes,

6 using chloranil and benzal chloride as quaternizing agents. Compounding recipes were as follows:

The stocks were milled, cured 30 minutes at 307 F., and physical properties determined. The following results were obtained:

Quaternizing Agent Chloranil Benzal Chloride Compression set, percent 9. Tensile, p. s. i., 80 F., original 2,330 Elongation, percent, 80 F., original 150 Tensile, p. s. i., oven aged 24 hrs. at 212 F 1, 690 Elongation, percent, oven aged 24 hrs. at 212 F 80 125 Shore Hardness 79 71 compounded MS 1% 63 36.5 Freeze point:

Gehman, C 65 67 Electrical resistivity, megohm/cm 15, 700 36 Wet tensile, p. s. i,, Skydrol 980 555 Wet tensile, p. s. i., 70/30 isooctane/toluene 530 355 Elongation, percent, 70/30 isooctane/toluene 60 i0 Elongation, percent, Skydrol 85 105 Swelling, percent, 70/30 isooctane/toluene 95. 9 115.8 Swelling, percent, Skydrol 66. 4 71. 9 Extraction, percent, 70/30 isooctane/toluene. 6. 9 7. 8

Example VI An 85/15 butadiene/Z-methyl--vinylpyridine polymer was prepared at 122 F. using the following polymerization recipe:

Sodium salt of condensed alkyl aryl sulfonic acid.

A conversion of 59 percent was reached in 14.7 hours. The rubber had a final Mooney value (ML-4) of 59.

Masterbatches were prepared with the polymer and withNo. I smoked sheet on a roll mill in which 50 parts of carbon black (Philblack 0) were incorporated. To these masterbatchcs chloranil was added in the amounts of 0, 0.25, 0.5, 2.0 and 5.0 parts per 100 parts of the rubber while maintaining the temperature below 180 F. using a cold mill. Each stock was subsequently mixed for minutes, the temperature being adjusted to give a final batch temperature of 320 to 350 F. and a second portion of each stock was mixed at a temperature to give a temperature in the range of 250 to 270 F., this mixing being done in a Banbury mixer. The mixes are described as follows, the designation OK indicating that the material was suitable for further processing:

PHR Dump Description Chlo- Rubber Tcm- Moon ey ranil perature M5 14 Stocks Mixed at 320-350 F.

Bd/MVP 315 OK 50 Bd/MVP 320 OK. 66 Bd/MVP- 330 OK Bd/MVP 330 Partially powdered. Powdered" OK 50 46 M 53 72 Bd/MVP 260 46 Bd/MVP 275 66 Bd/MVP 270 Ok 80 Bd/MVP 260 So tough ked out at 67, again at 11, again at 12.5, batch dumped. 260 Stalled the motor at 9 minutes, stock set-up. 245 OK 41 250 40 255 30 270 71 260 In Examples I through V the chloranil was incorporated in the polymer while maintaining the temperature of the stock below 230 F. by circulating cooling water through the rolls. This temperature limitation is important because heating to a higher temperature, as illustrated in Example VI, will cause the mixture to set up on the mill. This will prohibit further processing. This appears to be a peculiarity of this type of rubber due to the fact that chloranil acts in the dual capacity of a vulcanizing agent and a quaternizing agent. Its use as a vulcanizing agent has previously been known for natural rubber. Furthermore, it has been suggested that chloranil be incorporated with rubbers of this type but in much smaller amounts than I use. When the small amounts are used it is possible to handle the material in accordance with the teaching of the prior art.

In place of the pyridine derivatives used in the above examples, I can use a great many additoinal heterocyclic nitrogen bases. Preferred are those of the pyridine and quinoline series containing a vinyl or alpha-methyl-vinyl group. The polymers used as starting materials in this invention include homopolymers of the polymerizable heterocyclic nitrogen bases and copolymers thereof with materials copolymerizable therewith, such as conjugated dienes; styrene; various substituted styrenes, such as alkyl, alkoxy, and halogen-substituted styrenes; acrylonitrile; methacrylonitrile; methyl acrylate; methyl methacrylate; ethyl acrylate; butyl acrylate; and the like. Polymers prepared from various mixtures of heterocyclic nitrogen bases containing a vinyl or alpha-methylvinyl group with one or more other polymerizable materials are also applicable as well as terpolymers prepared from a heterocyclic nitrogen base containing a vinyl or alpha-methylvinyl group and two othertypes of monomers, e. g., a conjugated diene and a compound such as styrene, acrylo nitrile, methyl acrylate, or the like.

The nitrogen containing monomers suitable for use in my invention are those having the structure where R is selected from the group consisting of hydrogen, alkyl, vinyl, alpha-methylvinyl, nitro, alkoxy, halo, hydroxy, cyano, aryloxy, aryl, and combinations of these groups such as haloalkyl, alkylaryl, hydroxyaryl, and the like; at least one and not more than two of said groups being selected from the group consisting of vinyl and alpha-methylvinyl. it is preferred, in order to avoid steric hindrance, that the total number of carbon atoms in the substituted groups be not greater than 12. Examples of such compounds are 2-vinylpyridine; 2,5-divinylpyridine; 2-rnethyl-5--vinylpyridine; 2-vinyl--5-ethylpyridine; 2,3,4-trimethyl--vinylpyridine; 3,4,5,6-tetramethyl-2-vinylpyridine; 3-ethyl-5-vinylpyridine; 2,6-diethyl-4- vinylpyridine; 2-isopropyl 4-nonyl-5-vinylpyiridine; 2- rnethyl-S-undecyl 3-vinylpyridine; 3-dodecyl-4,5-divinylpyridine; 2,4-dimethy1-5,6-dipentyl-3-vinylpyridine; 2- decyl-S alpha-methylvinyl)pyridine; 3,5-di(alpha-methylvinyl)pyridine; 3-nitro-2-vinylpyridine; 2-vinyl-4-hydroxy- S-nitropyridine; 2-vinyl-3-methyl-S-ethylpyridine; 2-rnethoxy-4-ch1oro-6-vinylpyridine; 3 vinyl-S-ethoxypyridine; 2-vinyl-4,5-dichloropyridine; Z-(aIpha-methylvinyl)-4-hydroxy-G-cyanopyridiue; 2 vinyl-4-phenoxy-5-methylpyridine; 2-cyano-5-(alpha-methylvinyl)pyridine; 3-vinyl-5- phenylpyridine; Z-(para-methylphenyl)-3-vinyl-4-methylpyridine; 3-vinyl-5-(hydroxyphenyl) pyridine; 2-vinylquinoline; 2-vinyl-4-ethylquinoline; 3-vinyl-6,7-di-n-propylquinoline; 2-methyl-4-nonyl-6-vinylquinoline; 4(alpharnethylvinyl) 8 dodecylquinoline; 3 vinylisoquinoline; l,6-dirnethyl-3-vinylisoquinoline; 2 vinyl-4-benzylquinoline; 3-vinyl-5-chloroethylquinoline; 3-vinyl-5,6-dichloroisoquinoline; 2-vinyl-6-ethoxy-7-methylquinoline; 3-vinyl- 6-hydroxymethylisoquinoline; etc.

The conjugated dienes employed are preferably those which contain from four to six, inclusive, carbon atoms per molecule and include 1,3-butadiene, isoprene, piperylene, methylpentadiene, 2,3-dimethyl-1,3-butadiene, chloroprene, and others. However, conjugated dienes having more than six, such as eight, carbon atoms per molecule can also be used. Furthermore, various alkoxy, such as methoxy and ethoxy, and cyano derivatives of these conjugated dienes are also applicable.

For the production of the copolymers, the amount of a conjugated diene employed is generally in the range from to 98 parts per 100 parts by weight of the total monomeric material and the amount of copolymerizable heterocyclic nitrogen base employed is in the range from 75 to 2 parts per 100 parts by weight of the total monomeric material, the proportions of the monomeric material being dependent to a large extent upon the type of copolymer desired.

The amount of chloranil used Will generally be in the range between 3 and 20 parts by weight, preferably between 3 and 15 parts by weight, per 100 parts of rubbery copolymer.

Chloranil can be incorporated into the rubbery copolymers by any suitable means. One convenient method is to add it on the mill along with other compounding ingredients. This quaternizing agent is reactive under the conditions ordinarily employed for curing a rubber stock. This involves heating at a temperature of 250 to 350 F. for 5 to 90 minutes in most cases.

In addition to their oil resistance, the products of this invention exhibit excellent tensile strength and low temperature properties. They are useful in the manufacture of gaskets and other articles which come in contact with hydrocarbon solvents and hydraulic fluids such as high boiling phosphate esters.

As many possible embodiments may be made of this invention without departing from the scope thereof, it is to be understood that all matter herein set forth is to be interpreted as illustrative and not as unduly limiting the invention.

I claim:

1. A method of preparing an oil resistant rubber comprising mixing a rubbery conjugated diene/heterocyclic nitrogen base polymer with compounding ingredients including a vulcanizing agent and chloranil while maintaining the temperature below 230 F., the amount of said chloranil being in the range of 3 to 20 parts by weight per 100 parts of said rubbery polymer, and thereafter heating the resulting mixture at a temperature of 250 to 350 F. for 5 to minutes to cure the same.

2. A method of preparing an oil resistant rubber comprising mixing a rubbery butadiene/2-vinylpyridine polymer with compounding ingredients including a vulcanizing agent and chloranil while maintaining the temperature below 230 F., the amount of said chloranil being in the range of 3 to 20 parts by weight per parts of said rubbery polymer, and thereafter heating the resulting mixture at a temperature of 250 to 350 F. for 5 to 90 minutes to cure the same.

3. A method of preparing an oil resistant rubber comprising mixing a rubbery butadiene/Z-methyl-S-vinylpyridine polymer with compounding ingredients including a vulcanizing agent and chloranil while maintaining the temperature below 230 F., the amount of said chloranil being in the range of 3 to 20 parts by weight per 100 parts of said rubbery polymer, and thereafter heating the resulting mixture at a temperature of 250 to 350 F. for 5 to 90 minutes to cure the same.

4. A method of preparing an oil resistant rubber comprising mixing a rubbery butadiene/2-vinly-5-ethy1pyridine polymer with compounding ingredients including a vulcanizing agent and chloranil while maintaining the temperature below 230 F., the amount of said chloranil being in the range of 3 to 20 parts by weight per 100 parts of said rubbery polymer, and thereafter heating the resulting mixture at a temperature of 250 to 350 F. for 5 to 90 minutes to cure the same.

5. A method of producing an oil resistant rubber comprising reacting rubbery butadiene/2-methyl-5-vinylpyridine polymer with compounding ingredients including sulfur and chloranil while maintaining the temperature below 230 F., the amount of said chloranil being in the range of 3 to 20 parts by weight per 100 parts of said rubbery polymer, and thereafter heating the resulting mixture at a temperature of 250 to 350 F. for a period of 5 to 90 minutes to cure the same.

6. The product produced by the process of claim 1.

7. The product produced by the process of claim 3.

References Cited in the file of this patent UNITED STATES PATENTS 2,658,092 Barton NOV. 3, 1953 

1. A METHOD OF PREPARING AN OIL RESISTANT RUBBER COMPRISING MIXING A RUBBERY CONJUGATED DIENE/HETEROCYCLIC NITROGEN BASE POLYMER WITH COMPOUNDING INGREDIENTS INCLUDING A VULCANIZING AGENT AND CHLORANIL WHILE MAINTAINING THE TEMPERATURE BELOW 230*F., THE AMOUNT OF SAID CHLORANIL BEING IN THE RANGE OF 3 TO 20 PARTS BY WEIGHT PER 100 PARTS OF SAID RUBBERY POLYMER, AND THEREAFTER HEATING THE RESULTING MIXTURE AT A TEMPERATURE OF 250 TO 350*F. FOR 5 TO 90 MINUTES TO CURE THE SAME. 